Stage 1 of 8 · Tour du Mont Blanc

Chamonix-Mont-Blanc → Bionnay

Distance

21.1 km

Ascent

+1,151 m

Descent

-2,029 m

Est. Time

7h 49m

Altitude

975.7–2,468.5 m

Type

point-to-point

🏔️ Mountainous❄️ Alpine

Trail route lab

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21.1 km Distance1,151 m Climb7h 49m Est. time2,469 m High pointHARD Difficulty

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🚌

Getting Here

Brevent (bus stop)

1842m from trailhead · ~23 min walk

🚌

Getting Out

Bionnay (bus stop)

787m from trail end · ~10 min walk

Elevation Profile

Flat (<5%) Gentle (5–10%) Moderate (10–15%) Steep (15–25%) Very steep (>25%)

Route Map

🗺️ Open in Planner → | 🏔️ View 3D Flyover →

Segment Breakdown

Auto-analyzed from the elevation profile. Each segment shows the dominant character for planning your effort.

Segment	Dist	↑ / ↓	Time	Character
Chamonix-Mont-Blanc → km 2.2 (2469m) 2,074–2,469m	2.2 km	+442m / -48m	1h 12m	🔺 Steep Climb
km 2.2 (2469m) → km 16.3 (1674m) 976–2,469m	14.1 km	+770m / -1565m	4h 53m	📉 Descending
km 16.3 (1674m) → Bionnay 1,198–1,674m	4.8 km	+89m / -565m	1h 22m	🔻 Steep Descent
Total	21.1 km	+1,151m / -2,029m	7h 28m

Pace & Fuel Calculator

Adjust your flat 10K pace to see personalized finish time, calorie burn, and hydration needs.

Your flat 10K pace 7:00 /km

4:00 /km (elite) 12:00 /km (leisure)

Fast Hiker / Jogger

Est. Finish Time

4h 42m

Calories

3,822 kcal

Water Needed

3.9 L

Effort Distance

42.8 km

flat-equivalent

🍫 Recommended: ~45g carbs/hr (212g total) 🧂 Electrolytes: ~2351mg sodium/hr 🩹 Consider anti-chafe and blister prevention

Terrain Analysis

Runnability

Steep / Technical

% of route below 15% gradient

Climb Ratio

55 m/km

Steep profile

↑ 1,151m ↓ 2,029m

Surface & Technicality

Terrain Difficulty Breakdown

Runnable Flat (15%) Easy Grade (15%) Moderate Climb (26%) Steep (45%)

⛰️ Highly technical route. Power-hiking the steep sections is expected.

Current Conditions

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Conditions for July

ℹ️ Shoulder season

Snow Risk

Unlikely

Mud Risk

10%

Low

Ice Risk

Unlikely

✅ Snow unlikely at this elevation in July. Trail conditions expected to be clear.

Best months: 5, 6, 7, 8, 9, 10

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Suggested Gear List

Auto-generated based on 21.1 km, 1151m ascent, max altitude 2468.5m, ~8h duration.

Essential 8 items

👟
Trail running shoes / hiking boots

Required for any trail
📱
Phone (charged) + offline map

Navigation & emergency contact
💧
3L hydration vest

No water sources on route
🍫
Trail mix, bars & sandwich

Est. 4549 kcal burn
🧴
Sunscreen SPF 50+

UV intensifies above 2000m
🧢
Sun hat / cap

Exposed alpine terrain
🧥
Windbreaker / shell jacket

Summit at 2468.5m — wind chill
🆘
Emergency space blanket

Critical for preventing hypothermia if you stop moving